Overview
The purpose of this blog post is to draw attention to a critical vulnerability identified in LuaJIT, a Just-In-Time Compiler for Lua programming language. This vulnerability, tagged as CVE-2024-25176, could potentially lead to a system compromise or data leakage if exploited. It is relevant to all developers, system administrators, and users who are running applications developed with LuaJIT up to version 2.1. With a severity score of 9.8, this is a high-risk vulnerability that demands immediate attention.
Vulnerability Summary
CVE ID: CVE-2024-25176
Severity: Critical, CVSS score: 9.8
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and data leakage
Affected Products
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Product | Affected Versions
LuaJIT | Up to 2.1
How the Exploit Works
This exploit takes advantage of a stack-buffer-overflow in the lj_strfmt_wfnum function located in the lj_strfmt_num.c file of the LuaJIT platform. An attacker can overflow the buffer by supplying it with more data than it can handle, causing the stack to overflow and overwrite adjacent memory areas. This can lead to arbitrary code execution, giving the attacker the ability to compromise the system or leak sensitive data.
Conceptual Example Code
Here’s a theoretical example of how the vulnerability might be exploited. In this case, the attacker crafts a special Lua script that when executed, overflows the buffer in the lj_strfmt_wfnum function.
-- Sample Lua script to exploit the vulnerability
local exploit = string.rep("A", 5000) -- Creates a string with 5000 "A", enough to overflow the buffer
local result = string.format("%f", exploit) -- Calls the vulnerable function with the overflowing string
Mitigation
The most effective mitigation for this vulnerability is to apply the latest patch from the vendor. If this is not immediately possible, a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can be used as a temporary measure to detect and block potential exploitation attempts. However, these measures will not completely eliminate the vulnerability, so applying the vendor’s patch should be the ultimate goal.
It’s important to note that cybersecurity is an ongoing process. Regular software updates, continuous monitoring, and prompt response to identified vulnerabilities are vital to ensuring the security of your systems.